The BadNot fast enough to justify the price savings compared to Intel's chips; next-gen Intel quad-core due out soon could further the performance gap.

The Bottom LineAMD's new Phenom quad-core CPU has little to recommend it over competing chips from Intel. The Phenom is marginally less expensive, but not enough to make up for its subpar performance. Unless AMD drops prices more aggressively, it looks like Intel will maintain its grasp on the CPU market for the foreseeable future.

For raw performance, AMD's Athlon 64 X2 chips have lingered behind their Intel Core 2 Duo counterparts all year. Only aggressive pricing from AMD kept its old dual-core CPUs in systems and on store shelves. According to our testing, AMD will have to work similar magic with its new quad-core Phenom chips. If you want a quad-core PC now, and you can find a prebuilt PC that uses a Phenom 9500 for significantly less than a similar desktop with an Intel Core 2 Quad Q6600, go for it. But unless you can find it for an exceptional price, we advise against the Phenom right now, because its performance simply isn't there.

AMD has made much of the fact that its Phenom is the first "true" quad-core CPU. Technically, this is correct. While Intel's Core 2 Quad design basically melds two dual-core chips together, AMD's Phenom is the first to include four cores that all share at least one level of cache; in this case, the Level 3 cache. Similar to recent advances in 3D chip design, the Phenom's unified L3 cache provides a data store the size of which changes depending on the amount of data coming through. Its flexibility ranges from pumping out one large chunk of data to a single core, or sending four smaller chunks across all four processors. In theory, that dynamic distribution of work should give Phenom an advantage over Intel's Core 2 design. The problem is that neither the size of the data chunks nor the speed at which Phenom can process them, give AMD's new chips enough of a boost.

The chart below gives the significant details as to how the Phenom 9500 and Intel's Core 2 Quad Q6600 stack up against each other: